A human hemoglobin possessing abnormal alpha chains that contain 172 amino acids, rather than the normal number of 141. Hb Constant Spring seems to be the result of a nonsense mutation that converted a stop codon into a codon specifying an amino acid (glutamine, in this case). The 30 additional amino acids must be coded by adjacent base sequences that normally are not transcribed, or, if transcribed, not translated. The designation Constant Spring comes from the region of the island of Jamaica where the mutant hemoglobin was discovered.
Subjects: Genetics and Genomics.